Catalyst tools are crafted from flexible silicone to allow artists a new form of expression. Designed for heavy-body acrylics and mediums but can also work with oils acrylics water miscible oils plaster clay and even frosting. Heat-resistant for encaustic work as well. Easy to wipe clean and solvent resistant. Catalyst blades can be separated from their wood handles for cleaning and easily replaced when dry. FDA-approved silicone. Blade 3 (green) 15mm